Signal processing circuit null for normal mode rejection of CCD video

摘要

PURPOSE:To improve picture quality by finding differential signals in a horizontal direction, a vertical direction, and a time base direction. and eliminating a noise component mixed in a picture element signal by a signal with the intermediate value of the differential signals. CONSTITUTION:The differential signal with three delay signals obtained by a one-picture element delay element 2a, a one-line delay element 3a, and a one-field delay element 4a is found from the output signal of a solid-state image pickup element 1a for black and white. The differential signal is selected at a median value decision circuit 6, and a noise signal can be obtained. When the noise signal shows a value less than a threshold value decided by the value of an original output signal, it is recognized as a noise, therefore, the gain of a gain variable circuit 9 is set at 1, however, when it exceeds the threshold value, it is recognized as change in the signal, therefore, the gain is set at 0. Thereby, it follows that noise elimination when the change occurs in two directions is interrupted, and signal deterioration can be prevented from occurring, and the noise elimination can be performed without deteriorating solution.